HIV-1 dynamics and coreceptor usage in Maraviroc-treated patients with ongoing replication.

There is evidence that HIV-1 evolution under maraviroc (MVC) pressure can lead to the selection of either X4-tropic variants and/or R5-tropic, MVC-resistant isolates. However, the viral dynamics of HIV-1 variants in patients with virological failure (VF) on MVC-containing regimens remain poorly studied. Here, we investigated the V3 loop evolution of HIV-1 on MVC in relation to coreceptor usage and the nature of HIV-1 quasispecies before MVC therapy using bulk population sequences and ultradeep sequencing. The majority of patients had no detectable minority X4 variant at baseline. The evolution of tropism was followed up until VF and showed three possibilities for viral evolution in these patients: emergence of preexisting X4 variants, de novo selection of R5 variants presenting V3 loop mutations, or replication of R5 variants without selection of known mutations.

Stimulation of the human RAD51 nucleofilament restricts HIV-1 integration in vitro and in infected cells.

Stable HIV-1 replication requires the DNA repair of the integration locus catalyzed by cellular factors. The human RAD51 (hRAD51) protein plays a major role in homologous recombination (HR) DNA repair and was previously shown to interact with HIV-1 integrase (IN) and inhibit its activity. Here we determined the molecular mechanism of inhibition of IN. Our standard in vitro integration assays performed under various conditions promoting or inhibiting hRAD51 activity demonstrated that the formation of an active hRAD51 nucleofilament is required for optimal inhibition involving an IN-DNA complex dissociation mechanism. Furthermore we show that this inhibition mechanism can be promoted in HIV-1-infected cells by chemical stimulation of the endogenous hRAD51 protein. This hRAD51 stimulation induced both an enhancement of the endogenous DNA repair process and the inhibition of the integration step. Elucidation of this molecular mechanism leading to the restriction of viral proliferation paves the way to a new concept of antiretroviral therapy based on the enhancement of endogenous hRAD51 recombination activity and highlights the functional interaction between HIV-1 IN and hRAD51.

Cervical human papillomavirus and HIV infection in women of child-bearing age in Abidjan, Côte d'Ivoire, 2010.

BACKGROUND: We sought to document the association of Human immunodeficiency Virus (HIV) infection and immunodeficiency with oncogenic Human Papillomavirus (HPV) infection in women with no cervical neoplastic lesions identified through a cervical cancer screening programme in Côte d'Ivoire. METHODS: A consecutive sample of women stratified on their HIV status and attending the national blood donor clinic or the closest HIV clinic was recruited during a cervical cancer screening programme based on the visual inspection. Diagnosis of HPV infection and genotype identification were based on the Linear Array; HPV test. RESULTS: A total of 445 (254 HIV-positive and 191 HIV-negative) women were included. The prevalence of oncogenic HPV infection was 53.9% (95% confidence interval (CI) 47.9-59.9) in HIV-positive women and 33.7% (95% CI 27.1-40.3) in HIV-negative women (odds ratio (OR)=2.3 (95% CI 1.5-3.3)). In multivariate analysis, HIV-positive women with a CD4 count <200 cells mm(3) or between 200 and 499 cells mm(3) were more likely to harbour an oncogenic HPV compared with women with a CD4 count ≥500 cells mm(3) with OR of 2.8 (95% CI 1.1-8.1) and 1.7 (95% CI 1.0-2.9), respectively. CONCLUSION: A high prevalence of oncogenic HPV was found in women with no cervical neoplastic lesions, especially in HIV-positive women. Despite antiretroviral use, immunodeficiency was a main determinant of the presence of oncogenic HPV.

Structure-analysis of the HIV-1 integrase Y143C/R raltegravir resistance mutation in association with the secondary mutation T97A.

The HIV-1 integrase (IN) mutations Y143C/R are known as raltegravir (RAL) primary resistance mutations. In a previous study (S. Reigadas et al., PLoS One 5:e10311, 2010), we investigated the genetic pathway and the dynamics of emergence of the Y143C/R mutations in three patients failing RAL-containing regimens. In these patients, the Y143C/R mutation was associated with the T97A mutation. The aim of the present biochemical and molecular studies in vitro was to evaluate whether the secondary mutation, T97A, associated with the Y143C/R mutation could increase the level of resistance to RAL and impact IN activities. Site-directed mutagenesis experiments were performed with expression vectors harboring the region of the pol gene coding for IN. With a 3'-end processing assay, the 50% inhibitory concentrations (IC(50)) were 1.2 µM, 1.2 µM, 2.4 µM (fold change [FC], 2), and 20 µM (FC, 16.7) for IN wild type (WT), the IN T97A mutation, the IN Y143C/T97A mutation, and the IN Y143R/T97A mutation, respectively. FCs of 18 and 100 were observed with the strand transfer assay for IN Y143C/T97A and Y143R/T97A mutations, with IC(50) of 0.625 µM and 2.5 µM, respectively. In the strand transfer assay, the IN Y143C or R mutation combined with the secondary mutation T97A severely impaired susceptibility to RAL compared to results with the IN Y143C or R mutation alone. Assays without RAL suggested that the T97A mutation could rescue the catalytic activity which was impaired by the presence of the Y143C/R mutation. The combination of the T97A mutation with the primary RAL resistance mutations Y143C/R strongly reduces the susceptibility to RAL and rescues the catalytic defect due to the Y143C/R mutation. This result indicates that the emergence of the Y143C/R/T97A double-mutation pattern in patients is a signature of a high resistance level.

Hepatitis C virus (HCV) protease variability and anti-HCV protease inhibitor resistance in HIV/HCV-coinfected patients.

OBJECTIVES: Data on the natural selection of isolates harbouring mutations within the NS3 protease, conferring resistance to hepatitis C virus (HCV) protease inhibitors (PIs), are limited for HIV/HCV-coinfected patients. The aim of this study was to describe the natural prevalence of mutations conferring resistance to HCV PIs in HIV/HCV-coinfected patients compared with HCV-monoinfected patients. METHODS: The natural prevalences of HCV PI resistance mutations in 120 sequences from HIV/HCV-coinfected patients (58 genotype 1a, 18 genotype 1b and 44 genotype 4) and 501 sequences from HCV-monoinfected patients (476 genotype 1 and 25 genotype 4), retrieved from GenBank as a control group, were compared. RESULTS: Of 76 sequences from HIV/HCV genotype 1-coinfected patients, six (7.9%) showed amino acid substitutions associated with HCV PI resistance (V36L, n=1; V36M, n=2; T54S, n=2; R155K, n=1). In 31 of 476 (6.5%) HCV genotype 1 sequences retrieved from the GenBank database, HCV PI resistance mutations were found. The difference was not statistically significant (P=0.6). All of the sequences from HIV/HCV genotype 4-coinfected patients and those retrieved from the GenBank database had amino acid changes at position 36 (V36L). CONCLUSION: Our study suggests that the natural prevalence of strains resistant to HCV PIs does not differ between HCV-monoinfected and HIV/HCV-coinfected patients. Further studies on larger cohorts are needed to confirm these findings and to evaluate the impact of these mutations in clinical practice.

Pandemic influenza A(H1N1) 2009: molecular characterisation and duration of viral shedding in intensive care patients in Bordeaux, south-west France, May 2009 to January 2010.

From May 2009 to January 2010, the Virology Laboratory at the University Hospital of Bordeaux received more than 4,000 nasopharyngeal samples from the Aquitaine region (south-west France) for the diagnosis of pandemic influenza A(H1N1)2009. Eighty-three infected patients deteriorated and were admitted to intensive care units. Our study focused on 24 of these patients. Positivity for influenza A(H1N1)2009 was monitored by realtime PCR and duration of viral shedding was determined. The first available sample of each patient was analysed for bacterial, fungal and viral co-infection. We observed six bacterial (or bacterial/fungal) co-infections and one viral co-infection with respiratory syncytial virus. The samples were analysed for the presence of the neuraminidase H275Y (N1 numbering) mutation, which confers resistance to oseltamivir, by realtime PCR of the neuraminidase gene. No H275Y mutation was observed in any of the viral strains screened in this study. In parallel, a fragment of the haemagglutinin gene encoding amino acid residues 173 to 362 was sequenced to detect mutations that had been reported to increase the severity of the disease. Two patients were infected by strains bearing the D222G (H3 numbering) mutation. The viral shedding of A(H1N1)2009 in this study ranged from four to 28 days with a median of 11 days.

Membrane effects of thyrotropin-releasing hormone and estrogen shown by intracellular recording from pituitary cells.

The effects of thyrotropin-releasing hormone and 17 beta-estradiol on the electrical membrane properties of a prolactin-secretin pituitary cell line (GH3/B6) were studied with intracellular microelectrode recordings. Of the cells tested, 50 percent were excitable and displayed calcium-dependent action potentials when depolarized. When injected directly on the membrane of an excitable cell, thyrotropin-releasing hormone and 17 beta-estradiol induced action potentials within 1 minute. The spiking activity was preceded by a progressive increase of the input resistance without any detectable change in the resting membrane polarization. The results reveal a rapid effect of both substances on the membrane of GH3/B6 cells. In the case of thyrotropin-releasing hormone, which has both a short-term effect on release of prolactin and a long-term effect on its synthesis, the induced electrical activity may be associated with the stimulation of prolactin production. The physiological implication of 17 beta-estradiol-induced, calcium-dependent spiking activity remains to be elucidated.

Oseltamivir susceptibility in south-western France during the 2007-8 and 2008-9 influenza epidemics and the ongoing influenza pandemic 2009.

The recent emergence of seasonal influenza A(H1N1) strains resistant to oseltamivir makes it necessary to monitoring carefully the susceptibility of human influenza viruses to neuraminidase inhibitors. We report the prevalence of the oseltamivir resistance among influenza A viruses circulating in south-western France over the past three years: seasonal influenza A(H1N1), seasonal influenza A(H3N2), and the influenza A(H1N1)v viruses associated with the ongoing 2009 pandemic. The main result of the study is the absence of oseltamivir resistance in the pandemic H1N1 strains studied so far (n=129).

Prolonged shedding of influenza A(H1N1)v virus: two case reports from France 2009.

We observed a prolonged shedding of virus 14 and 28 days after symptom onset in two patients with pandemic H1N1 influenza, who did not have immunodepression and were treated with neuraminidase inhibitor. This prolonged shedding was not associated with the emergence of resistance mutation H275Y in the viral neuraminidase gene.

The novel HBx mutation F30V correlates with hepatocellular carcinoma in vivo, reduces hepatitis B virus replicative efficiency and enhances anti-apoptotic activity of HBx N terminus in vitro.

OBJECTIVE: We aimed to investigate HBx genetic elements correlated with hepatitis B virus (HBV) -related hepatocellular carcinoma (HCC) and their impact on (a) HBV replicative efficiency, (b) HBx binding to circular covalently closed DNA (cccDNA), (c) apoptosis and cell-cycle progression, and (d) HBx structural stability. METHODS: This study included 123 individuals chronically infected with HBV: 27 with HCC (77.9% (21/27) genotype D; 22.1% (6/27) genotype A) and 96 without HCC (75% (72/96) genotype D; 25.0% (24/96) genotype A). HepG2 cells were transfected by wild-type or mutated linear HBV genome to assess pre-genomic RNA (pgRNA) and core-associated HBV-DNA levels, HBx-binding onto cccDNA by chromatin immunoprecipitation-based quantitative assay, and rate of apoptosis and cell-cycle progression by cytofluorimetry. RESULTS: F30V was the only HBx mutation correlated with HCC (18.5% (5/27) in HCC patients versus 1.0% (1/96) in non-HCC patients, p 0.002); a result confirmed by multivariate analysis. In vitro, F30V determined a 40% and 60% reduction in pgRNA and core-associated HBV-DNA compared with wild-type (p <0.05), in parallel with a significant decrease of HBx binding to cccDNA and decreased HBx stability. F30V also decreased the percentage of apoptotic cells compared with wild-type (14.8 ± 6.8% versus 19.1 ± 10.1%, p <0.01, without affecting cell-cycle progression) and increased the probability of HBx-Ser-31 being phosphorylated by PI3K-Akt kinase (known to promote anti-apoptotic activity). CONCLUSIONS: F30V was closely correlated with HBV-induced HCC in vivo, reduced HBV replicative efficiency by affecting HBx-binding to cccDNA and increased anti-apoptotic HBx activity in vitro. This suggests that F30V (although hampering HBV's replicative capacity) may promote hepatocyte survival, so potentially allowing persistent production of viral progeny and initiating HBV-driven hepatocarcinogenesis. Investigation of viral genetic markers associated with HCC is crucial to identify those patients at higher risk of HCC, who hence deserve intensive liver monitoring and/or early anti-HBV therapy.

Influenza B burden during seasonal influenza epidemics in France.

CONTEXT: Seasonal flu outbreaks are linked to the circulation of influenza virus type A or B. Special attention has always been paid to influenza A epidemics; but recently, several studies have investigated the impact of influenza B virus epidemics, particularly as, since the 1980s, two antigenically different influenza B lineages co-circulate, raising the issue of vaccine matching. OBJECTIVES: We present the results of influenza B burden during nine influenza seasons (2003-2013) and vaccine matching of the circulating lineages. PATIENTS AND METHODS: Clinical and virological influenza surveillance data, collected by the Regional Groups for Influenza Surveillance Network in France, allows for studying the burden of influenza in the practice of the population of ambulatory care physicians. RESULTS AND CONCLUSION: Our analysis is based on 37,801 samples, of which 12,036 were virologically confirmed influenza cases (31.8%), including 3576 cases of influenza B (29.7% of influenza cases). Influenza B viruses significantly circulated during six seasons. For each season, the influenza B epidemic peaked later than the influenza A epidemic. Influenza B is very common in children of school age but also affects other age groups. Finally, more than one-third of the analyzed influenza B viruses belonged to a different lineage than the one used in the composition of the trivalent vaccine. Our results are comparable to those described in other countries.

Study of the concordance between p16 immunohistochemistry and HPV-PCR genotyping for the viral diagnosis of oropharyngeal squamous cell carcinoma.

OBJECTIVE: The diagnosis of HPV-related oropharyngeal cancer in clinical practice is based on p16 immunohistochemistry and PCR detection of viral DNA (HPV-PCR). The primary objective of this study was to evaluate the concordance between these 2 diagnostic tests. The secondary objective was to study the clinical characteristics of these patients. MATERIALS AND METHODS: This single-centre prospective study was conducted between February 2010 and July 2012. Immunohistochemical analysis of p16 and HPV-PCR were performed on tumour biopsies. Concordance was evaluated according to Cohen's kappa coefficient and was interpreted according to the Landis and Koch scale. The patients' clinical data were analysed as a function of the diagnostic test results. RESULTS: Seventy-one patients were included in this study. The prevalence of HPV was 43.7% according to p16 and 31% according to HPV-PCR. The concordance study revealed a kappa coefficient of 0.615. A tumour of the tonsil or base of the tongue was detected in 100% of p16+/HPV-PCR+ cases. Smoking and alcohol abuse were significantly less frequent among HPV+ patients regardless of the method of detection. These patients were older and presented tumours with a lower grade of histological differentiation. CONCLUSION: p16 immunohistochemistry or HPV-PCR used alone appear to be insufficient. These results confirm the high prevalence of HPV-related oropharyngeal squamous cell carcinoma (OSCC) and the previously reported specific clinical and histological features, apart from age. It appears essential for future clinical trials to be stratified according to smoking and tumour HPV status, defined by means of reliable virological tests targeting E6/E7 mRNA and no longer a simple positive response to the p16 marker, as is frequently the case at the present time. New tests suitable for use in routine practice therefore need to be developed.

Human polyomavirus JC latency and reactivation status in blood of HIV-1-positive immunocompromised patients with and without progressive multifocal leukoencephalopathy.

BACKGROUND: Human polyomavirus JC (JCV) induces human progressive multifocal leukoencephalopathy (PML) in patients with AIDS. Peripheral blood mononuclear cells (PBMC) of HIV-1-positive immunocompetent and immunocompromised patients can harbour JCV genome, but their precise role in JCV latency or reactivation status before the onset of PML remains hypothetical. OBJECTIVES: To assess JCV latency or reactivation status in PBMC of HIV-1-positive immunocompromised patients without PML. DESIGN: A group of 82 HIV-1-positive immunocompromised patients who did not have PML were compared with 10 patients with AIDS and PML and with 69 HIV-1-positive immunocompetent patients without PML. METHODS: DNA and total RNA were extracted from PBMC. The presence of JCV DNA was demonstrated by a semi-nested polymerase chain reaction (PCR). By using primer pairs specific for an early gene,T, and a late gene, VP1, the expression of both early and late gene mRNA in PBMC could be identified using reverse transcriptase (RT) PCR. RESULTS: JCV DNA was detected by PCR in 17.4% of 69 HIV-1-positive immunocompetent patients, in 23.2% of 82 HIV-1-positive immunocompromised patients, and in 60% of 10 patients with AIDS and PML. No correlation could be drawn between the detection of JCV DNA in the PBMC and the clinical or biological status of the HIV-1-positive patients. By using RT-PCR procedures, no expression of JCV early and late mRNA in PBMC was found in any patients. CONCLUSIONS: JCV DNA is detectable in the PBMC of 20.5% of 151 HIV-1-infected patients independently of the CDC (Centers for Disease Control and Prevention) stages of the infection. Moreover, our results suggest that active replication of JCV in PBMC appears to be absent or at least a very rare event in HIV-1-positive immunocompromised patients with and without PML.

Cell-associated HIV-1-DNA quantitation after highly active antiretroviral therapy-treated primary infection in patients with persistently undetectable plasma HIV-1 RNA.

OBJECTIVE: To determine the usefulness of cell-associated HIV-1-DNA quantification during the follow-up of highly active antiretroviral therapy (HAART)-treated primary-infected patients with persistently undetectable plasma RNA loads. PATIENTS AND METHODS: In 27 patients given HAART within a median of 24 days after symptomatic primary HIV infection, plasma and peripheral blood mononuclear cell (PBMC) HIV-1 RNA were less than 50 copies/ml and less than 50 copies/10(6) cells after 18 months of treatment. HIV-1 RNA and DNA were quantified every 6 months in PBMC in these 27 patients, 14 of whom accepted excision lymph node biopsy after month 18 for HIV-1-RNA and -DNA quantification in lymph node mononuclear cells (LNMC). RESULTS: The median decreases in plasma HIV-1 RNA, PBMC HIV-1 RNA and DNA over the 18 months of follow-up were 3.6 log (P< 0.005), 1.1 log (P< 0.05), and 1.0 log (P<0.001), respectively. HIV-1 DNA was detected in 92.3% of PBMC samples at baseline and at month 18. In LNMC, 100% of samples were detectable for HIV-1 DNA. CONCLUSION: In this highly selected population of patients with excellent plasma virological response under HAART, HIV-1 DNA showed a progressive decrease but was still detectable in 92.3% of samples at month 18, whereas all LNMC samples tested scored positive for HIV-1 DNA. The utility of proviral HIV-1-DNA monitoring was not clearly demonstrated in this 18-month follow-up of HAART-treated primary-infected patients. However, this finding could be reconsidered when using other therapeutic strategies such as structured treatment interruptions, reinforced treatment or additive immunotherapy.

Comparative assessment of quantitative HIV viraemia assays.

OBJECTIVE: To compare two published methods for determining plasma viraemia in HIV-seropositive patients, with reference to a cellular viraemia assay. PATIENTS, PARTICIPANTS: Three patient groups were defined according to CD4 cell count: group I, less than 200 x 10(6)/l (23 patients); group II, 200-500 x 10(6)/l (18 patients); and group III, greater than 500 x 10(6)/l (13 patients). METHODS: The two reported methodologies were applied to all fresh samples, simultaneously and on the same day. RESULTS: The two techniques did not differ significantly in the detection of plasma viraemia: 82.3% of group I patients and 55% of group II patients were positive, while all group III patients were negative. Cellular viraemia was positive for 96% of the overall population. CONCLUSIONS: These results, obtained in a network of seven French laboratories involved in clinical trials, confirm that both plasma viraemia and cellular viraemia are useful virological markers.

Detection of JC virus DNA in the peripheral blood leukocytes of HIV-infected patients.

OBJECTIVES: To assess whether JC virus (JCV) DNA is frequently harboured by peripheral blood leukocytes (PBL) in HIV-positive patients, before the onset of progressive multifocal leukoencephalopathy (PML). DESIGN: The polyomavirus JCV induces PML in immunocompromised persons and particularly AIDS patients. Leukocytes may play a central part in the onset of PML, but their precise role in JCV latency and reactivation still remains hypothetical. The controversial presence of JCV DNA in PBL has been, until now, investigated only among small groups of patients. We therefore studied 157 HIV-positive persons and compared them with 65 HIV-negative immunocompromised patients. METHODS: DNA was extracted from PBL. The presence of JCV DNA was demonstrated by the polymerase chain reaction (PCR) alone or combined with a molecular hybridization assay. RESULTS. The presence of JCV DNA was ascertained by PCR and hybridization in 28.9% of 135 HIV-infected persons at all stages of HIV infection and only 16.4% of 61 HIV-negative immunocompromised patients. No correlation could be drawn between the detection of JCV DNA and the clinical or biological status of the HIV-positive patients. CONCLUSIONS: JCV DNA is detectable in the PBL of 28.9% of HIV-infected persons, even in the early stages of infection. JCV is more seldomly amplified in HIV-negative immunocompromised patients. Further work is in progress to determine the prognostic value of the presence of JCV DNA in the blood of HIV-positive patients.

HIV-1 diversity in France, 1996-1998. The AC 11 laboratory network.

OBJECTIVE: To study the distribution of HIV-1 subtypes in France and to describe the characteristics of patients infected with non-B subtypes. METHODS: All adults who tested HIV-1 positive on Western blot for the first time in one of the participating laboratories between September 1996 and March 1998 were eligible, whether or not they had been diagnosed previously elsewhere. Data on age, sex, country of birth, HIV-transmission group, dates of the last negative and first positive HIV test and clinical stage were collected. Serotyping was performed with a peptide subtype-specific enzyme immunoassay on each plasma sample and genotyping with heteroduplex mobility assay on each non-B serotype-infected patient. Patients characteristics were compared in B and non-B subtypes. RESULTS: Of the 2168 HIV-positive patients included by 32 laboratories, subtype,results were available for 2042. Among those, 73.4% were men, 12.2% born in sub-Saharan Africa, 41.5% infected through heterosexual contact and 67.6% in CDC stage A. Among the 2042 patients, 1 725 (84.5%) were infected with B subtype. Among the 317 non-B subtypes, subtype A was predominant (66.9%); all other subtypes (C, D, E, F, G, H, O) were present. Factors independently associated with a non-B subtype were to be included in the Paris area [adjusted odds ratio (aOR), 1.6; 95% confidence interval (CI), 1.1-2.3], to be born in sub-Saharan Africa (aOR, 26.0; 95% CI, 17.5-37.8) and to be infected through heterosexual contact (aOR, 4.2; 95% CI, 2.8-6.4). CONCLUSIONS: In France, although B subtype is still predominant, all non-B subtypes are now present. The diversity of HIV strains may affect diagnostic tests and clinical practice, especially viral load measurements. Moreover, the decreased susceptibility of non-B subtypes to antiretroviral drugs emphasizes the importance of surveillance of HIV diversity.

Emergence of zidovudine and multidrug-resistance mutations in the HIV-1 reverse transcriptase gene in therapy-naive patients receiving stavudine plus didanosine combination therapy. STADI Group.

OBJECTIVE: Assessment of genotypic changes in the reverse transcriptase gene of HIV-1 occurring in antiretroviral naive patients treated by stavudine plus didanosine combination therapy. METHODS: Sequence analysis (codons 1-230) was performed after amplification of the reverse transcriptase gene from plasma samples collected at baseline and at the end of treatment from 39 previously treatment-naive patients treated for 24-48 weeks. RESULTS: At baseline, mutations associated with zidovudine resistance were detected in plasma from two patients: Asp67Asn/Lys219Gln and Leu210Trp. Among the 39 subjects, 18 (46%) developed mutations: one developed the Val75Thr/Ala mutation, four (10%) developed a Gln151Met multidrug-resistance mutation (MDR), associated in one of them with the Phe77Leu and the Phe116Tyr MDR mutations and 14 (36%) developed one or more zidovudine-specific mutations (Met41Leu, Asp67Asn, Lys70Arg, Leu210Trp, Thr215Tyr/Phe). The development of a Met41Leu zidovudine-specific mutation was associated with the development of a Gln151Met mutation in one patient. Other reverse transcriptase mutations known to confer resistance to nucleoside analogues were not detected. At inclusion, there was no statistical difference in HIV-1 load between patients who developed resistance mutations and those who did not. RNA HIV-1 load decrease was higher (P = 0.05) in patients who maintained a wild-type reverse transcriptase genotype (-2.22 log10 copies/ml) than in patients who developed resistance mutations (-1.14 log10 copies/ml). CONCLUSION: Stavudine/didanosine combination therapy is associated with emergence of zidovudine-related resistance or MDR mutations in naive patients. These findings should be considered when optimizing salvage therapy for patients who have received a treatment including stavudine/didanosine combination.

Impact of protease inhibitors on intrahepatic hepatitis C virus viral load.

During chronic hepatitis C, hepatitis C virus (HCV) load in plasma was shown to be higher in HIV-co-infected than in immunocompetent patients [1]. The reason for this increased HCV replication is not known. It may be as a result of HIV-induced immune deficiency [2], although some authors did not find any correlation with the CD4 cell count [3]. A direct interaction between HCV and HIV was also hypothesized [4]. Protease inhibitors (PI) used in highly active antiretroviral therapy (HAART) have no HCV reduction effect during the first months of treatment [5-8]. However, a decrease in HCV plasma load was recently described in patients treated with HAART for a year [9,10]. We therefore investigated the potential impact of HAART on intrahepatic HCV load.